1. Field of the Invention
The present invention relates to an antenna device suitably applicable to a communication device, such as a cellular phone terminal, and also relates to a communication device equipped with this antenna device.
2. Description of the Related Art
A handheld communication device, such as a cellular phone terminal, is designed to be easily carried or moved, so that the whole size thereof including an antenna unit is smaller the better. It is also preferable that the antenna is unobstructable.
Therefore, as disclosed in Japanese Patent Laid-Open No. 2005-167829 (Patent document 1) for example, a handheld communication terminal having a strap-shaped antenna device unit has been proposed in the art. In the patent document 1, the antenna deice unit includes an antenna member in which an antenna conductor is formed on a flexible substrate. Such an antenna device can be attached as a strap to the handheld communication terminal.
Therefore, the antenna device unit can stand clear of the handheld communication terminal and does not disfigure the handheld communication terminal.
In addition, Japanese Patent Laid-Open No. 7-147508 (Patent document 2) discloses an antenna for communication apparatus using an antenna member made of shape memory alloy. In other words, the antenna disclosed in Patent document 2 houses an antenna member in the housing of the communication member as far as possible at the time of out-of communication (nonuse). Alternatively, at the time of communication, the shape memory alloy that forms the antenna member is heated to raise the antenna so as to extend the antenna toward the outside of the housing.
Therefore, according to Patent document 2, it is convenient that the antenna is in a state of being housed at the time of out-of communication without hindrance. At the time of communication, the antenna is automatically raised to enhance the reception sensitivity.